The use case you're trying to solve
I'm trying to make sure that the version of firebase-tools used is the same as what is in my package.json. latest will probably be fine most of the time but there might be issues later.
Change to the action that would solve that use case
Add an option to read the version of firebase-tools version from package.json instead of requiring firebaseToolsVersion be set separately.
Other considerations
Maybe I could use some other tooling to sync up my package.json with firebaseToolsVersion but it would be nicer if action-hosting-deploy could do it on its own.